There are 20 (I searched, to double check) 20 separate threads here dealing with gas mileage. Some people say to go by the d.i.c., others say the d.i.c. is not accurate, go by the actual mileage on the odometer. What I do to keep track of mileage is - I reset the d.i.c. at every fill up and record the mileage for that fill up. When I quote my mileage (about 26 in city and 33.5 highway), it's the average of my fillups. BTW, I have only gone on the highway more than 50 miles twice since getting my HHR in Dec.

Please don't 'flame' me for asking this......those of you who don't trust the d.i.c. to track your fuel mileage - why do you trust that same d.i.c. to track your miles travelled? (Odometer)

 

That's a question I've wondered about myself. I just go by whatever my DIC says. I know the HHRs computer is going to be far more accurate than I would be with a calculator kind of half assed fudging the numbers and not taking all the things that affect gas milage into account.

 

Feel the same way!

 

The DIC indicates an "average" mpg, but average to what? Look at the average mph, mine will usually be in the mid 20's. I never drive 25 mph unless I'm in a neighborhood or on base. But that's the "average". Mine usually reads 1-2 mpg higher than a calculator. You want to test you odometer and speedometer? Set you cruise at 60, reset your trip odometer and set a stopwatch. It should take 60 seconds to travel 1 mile.

 

Do you reset the DIC every fillup?

Also I don't think using the numbers such as 400 miles driven and then filling with 13 gallons of gas is "half assing" things. Doesn't matter what the outside factors are, those numbers are still what mpg you got out of that tank of gas regardless. If I drive 80 mph to and from work everyday, I would expect my mpg to suffer

I asked before and nobody answered...how do you figure between what your city mpg is and highway? I see people posting "I get 26 city and 31 highway"

How are you coming up with that???


Goose

 

I usually reset the DIC on each tank, but not always. For my normal driving, I call that my city. Then I am on base, in town, and a 4 lane highghway that the limit is 55. SO it's a good round mixture I guess. But this is my city driving. I only use a highway mileage if I'm on a trip and use a tank only on the highway. My best highway milease was 29.1 and on that tank my DIC stated 29.4. It was 95% highway. I have seen the DIC read 33 before. But never with the calculator. I'm guessing that at that moment it was averaging 33.

Go figure.

 

The half assed comment was more aimed at myself. I know that's how I would be if I figured it out. I trust a computer's mathmatical abilities more than my own. Not to say I'm bad at math but computers are meant to crunch numbers so I let them do their job. As far as the average speed I believe it also calculates how much time you spend with your engine running going 0 MPH idling and so forth. Right now my HHR says my average speed is 27 MPH. I can travel at 80 MPH on the highway and it won't change a damn thing with my average speed because of all the stop and go driving I do.

 

Goose.....

For me at least.......

When I posted my city AND highway mileage it was based on specifically that. My city posting was based on several tanks of fuel for MY normal city driving..... averaged.

The highway mileage posting was based on what I experienced driving totally on Interstate Highways on a recent trip of 400miles each direction. Admittedly it did include about 2 miles of non Interstate....from gas fill-up and DIC reset to destination....about 2 miles off of the Interstate (with no stops in between).

Does that make sense????

Oh, and this is by using the DIC...which I believe is more accurate that anyones calculation. For Example, how do you know you replaced EXACTLY the amount of gas you used??? You don't. Gas pumps trigger and turn off at different sensitivities. Of course, you can top-off. But are you toping off at exactly the same volume......Gasoline is sensitive to temperatures and to temperature controlled containment. What was 10 gallons at 72F, might be 10.4 at 100F. If you use the DIC it uses the same algorithm all the time....so, you have consistantcy. Kind of like what others have said about, "believing the mileage/odometer but not the MPG". If the odometer is off 1 tenth of a mile for a reading of 450 miles, that's 45 miles difference (reductio ad absurdum). You get my point. My 2 cents.

 

I understand what you are saying guys..I guess i just base my MPG on a tank to tank basis, not overall...

Maybe I'm the opposite of most people..all my driving is highway with MAYBE 10% if lucky around town. I literally take a left a left and a left and I am on Rt 3 South heading into MA and don't get off the highway until 50 miles later and then about a 1/2 mile to my job. Right now for the past 3 or 4 fills I have not reset the DIC...it is reading 32.3...so based on what you guys are saying...that is my avg mpg?


Goose

 

I do it the simple way, I reset my trip meter at every refill. Right now I am getting over 400 miles to each tank. That is both city and highway. I do not know what that comes out per gallon, but I am very happy